/* eslint-disable no-inner-declarations */
(Drupal => {
  /**
   * Olivero helper functions.
   *
   * @namespace
   */
  Drupal.olivero = {};

  function isDesktopNav() {
    // @todo, I'm not sure we even need the .mobile-buttons container anymore.
    const navButtons = document.querySelector('.mobile-buttons');
    return (
      window.getComputedStyle(navButtons).getPropertyValue('display') === 'none'
    );
  }

  Drupal.olivero.isDesktopNav = isDesktopNav;

  const wideNavButton = document.querySelector('.nav-primary__button');
  const siteHeaderFixable = document.querySelector('.site-header__fixable');

  function wideNavIsOpen() {
    return wideNavButton.getAttribute('aria-expanded') === 'true';
  }

  function showWideNav() {
    if (isDesktopNav()) {
      wideNavButton.setAttribute('aria-expanded', 'true');
      siteHeaderFixable.classList.add('is-expanded');
    }
  }

  // Resets the wide nav button to be closed (its default state).
  function hideWideNav() {
    if (isDesktopNav()) {
      wideNavButton.setAttribute('aria-expanded', 'false');
      siteHeaderFixable.classList.remove('is-expanded');
    }
  }

  // Only enable scroll effects if the browser supports Intersection Observer.
  // @see https://github.com/w3c/IntersectionObserver/blob/master/polyfill/intersection-observer.js#L19-L21
  if (
    'IntersectionObserver' in window &&
    'IntersectionObserverEntry' in window &&
    'intersectionRatio' in window.IntersectionObserverEntry.prototype
  ) {
    const fixableElements = document.querySelectorAll('.fixable');

    function toggleDesktopNavVisibility(entries) {
      if (!isDesktopNav()) return;

      entries.forEach(entry => {
        // FF doesn't seem to support entry.isIntersecting properly,
        // so we check the intersectionRatio.
        if (entry.intersectionRatio < 1) {
          fixableElements.forEach(el => el.classList.add('js-fixed'));
        } else {
          fixableElements.forEach(el => el.classList.remove('js-fixed'));
        }
      });
    }

    function getRootMargin() {
      let rootMarginTop = 72;
      const { body } = document;

      if (body.classList.contains('toolbar-fixed')) {
        rootMarginTop -= 39;
      }

      if (
        body.classList.contains('toolbar-horizontal') &&
        body.classList.contains('toolbar-tray-open')
      ) {
        rootMarginTop -= 40;
      }

      return `${rootMarginTop}px 0px 0px 0px`;
    }

    function monitorNavPosition() {
      const primaryNav = document.querySelector('.site-header');
      const options = {
        rootMargin: getRootMargin(),
        threshold: [0.999, 1],
      };

      const observer = new IntersectionObserver(
        toggleDesktopNavVisibility,
        options,
      );
      observer.observe(primaryNav);
    }

    wideNavButton.addEventListener('click', () => {
      if (!wideNavIsOpen()) {
        showWideNav();
      } else {
        hideWideNav();
      }
    });

    siteHeaderFixable
      .querySelector('.site-header__inner')
      .addEventListener('focusin', showWideNav);

    // If skip link is clicked, ensure that the wide navigation closes so the header will not be covered up.
    document.querySelector('.skip-link').addEventListener('click', hideWideNav);

    monitorNavPosition();
  }

  document.addEventListener('keyup', e => {
    if (e.keyCode === 27) {
      // Close the search form.
      if (
        'toggleSearchVisibility' in Drupal.olivero &&
        'searchIsVisible' in Drupal.olivero &&
        Drupal.olivero.searchIsVisible()
      ) {
        Drupal.olivero.toggleSearchVisibility(false);
      }
      // Close the wide nav.
      else {
        hideWideNav();
      }
    }
  });
})(Drupal);